When asked “where do you taste?” most people will answer you correctly, the tongue. What many people don’t realise is that the tongue is actually only capable of detecting a limited number of different tastes. All the other flavours that people might describe are actually aromas. Yes, that’s right, in fact 70-85% of flavour is perceived in the nasal cavity.
When you chew a food you break it down into smaller pieces, you mix it with your saliva and you warm it up in the mouth. These actions have an affect on the various compounds that make up any given food.
Breaking down the food into smaller pieces increases its surface area and allows it to begin to dissolve into the saliva. Compounds in the saliva can then be detected by taste receptor cells which are housed in taste buds all over the tongue.
Warming the food up in your mouth allows aroma compounds to become airborne, or volatile, and travel up the back of the throat to your nasal cavity. Here they can dissolve into the mucus that lines your nasal cavity and be detected by olfactory receptors, your sense of aroma/smell.
So what can we actually taste on the tongue? There are only 5 widely recognised basic tastes that taste receptors exist for; sweet, salt, sour, bitter and umami, along with the recent addition of a sixth, but less widely regarded taste, of fat.
This taste is characterised by sugar. Humans are preprogrammed to like sweet foods as they would have been an important source of energy for us when food was scarce. Nowadays food is so readily available that we don’t need to seek out sugar rich foods so much, but the pleasure associated with eating them often overrides that.
This taste is characterised by salt and sodium ions. Humans are preprogrammed to like small amounts of salt and to find large amounts of salt unpleasant in order to balance the amount that we eat naturally. Many of us have inadvertently trained our taste buds to like more and more salt which isn’t ideal for our health. The good news is that you can train your taste buds back by gradually reducing the amount of salt in your diet.
Bitterness is often described as an unpleasant taste. Examples are the taste of an acetaminophen tablet if you don’t swallow it quickly enough, or the taste of quinine in tonic water. Ability to detect bitterness was primarily a human defence mechanism and is still used as such with compounds such as Bitrex that are added to potentially harmful products to avert consumption. Bitterness can however be a desirable, and even pleasant, taste in some products such as coffee, beer, chocolate and some green leafy vegetables.
This is characterised by acid e.g. citric acid found in lemon juice, and has a mouth watering effect. Imagine biting into a slice of freshly cut lemon and that is sourness for you! Although many foods contain acids and are often desirable to eat, is it thought that acid taste detection was actually a defence mechanism to avoid consumption of foods that may have started to decay or ferment and may therefore contain harmful bacteria.
Umami is a Japanese word meaning savoury and is characterised by monosodium glutamate (MSG). Many people describe this taste as broth-like or meaty. Foods such as mushrooms, tomatoes, fish sauce, soy sauce and parmesan cheese are naturally high in umami.
This has been identified by scientists more recently as a basic taste characterised by fatty acids. Scientists don’t yet have a good vocabulary with which to describe how these fatty acids taste except to say that they tend to be unpleasant, bitter and akin to oxidised or rancid oil/fat. It should not be confused with the often desirable mouthfeel that you get when eating fatty foods.
Humans have thousands of taste buds on the tongue and around other surfaces in the mouth, and each taste bud contains up to around 100 taste receptor cells. Back in 1901 a map of the tongue was drawn up to show which areas of the tongue perceived which tastes; bitter at the back, sweet at the tip, sour on back the sides, salt on the front sides. Nowadays we know this map to be inaccurate. In fact, receptors for all tastes are located over the entire surface of the tongue, along with the soft palate (roof of your mouth) and your throat. You even have taste receptors in your gut so that your body knows what nutrients it can uptake.
In addition to ‘taste’ the tongue also plays an important role in detecting physical properties of foods such as temperature and texture.
Next time you say you don’t like the taste of something you can ask yourself if it is really the aroma that you don’t like!
To learn more about Sensory Science and how it can help to grow your business contact Sarah Cowen or John Hale.